Refrigeration



c. F. KETTERING REFRIGERATION I Oct. 30, 1934.

Filed Jain. 2a, 1933 Patented Oct. 30, 1934 NlTED TES REFRIGERATIUN lllharles F. Kettering, Dayton,

Frigidaire Corporation,

ration of Delaware @hio, assignor to Dayton, @hio, a corpo- Application .lanuary 28, 1933, Serial No. 654,086

10 Claims.

This invention relates to refrigeration.

Heretofore in the operation of refrigerating apparatus in which the compressor is operated intermittently, the compressor often has been flooded by the flow of a large quantity of liquid refrigerant into the compressor from the evaporator at the beginning of the running cycle and this has either caused serious damage to the compressor or has caused it to operate noisily until all the liquid has been pumped through the compressor to the high side of the compressor. It is among the objects of this invention to provide means for preventing or delaying this flow of liquid refrigerant into the compressor while permitting a substantially uninterrupted flow of gaseous refrigerant tothe compressor.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompany.- ing drawing, wherein a preferred form of the present invention is clearly shown.

In the drawing:

Fig. 1 is a view, partly diagrammatic and partly cross sectional of a refrigerating apparatus embodying features of my invention; and

Fig. 2 is a modified form of a portion of the apparatus shown in Fig. 1.

A refrigerating apparatus embodying features of my invention includes, in general, a compressor 10, a condenser 11 and an evaporator 12. A refrigerant expansion device 13 is interposed between the condenser and the evaporator, and, in this particular embodiment, it is a continuously open refrigerant expansion device in the form of an elongated restricted orifice, or tube diagrammatically indicated by the line 14. vThe apparatus also includes a liquid refrigerant delay means or trap 15 interposed between the evaporator 12 and the compressor 10.

In some types of apparatus, the compressor 10 is driven by the rotorlfi of a motor having a starting winding 17 and a running winding 18, the motor compressor mechanism being enclosed within a hermetic casing diagrammatically indicated at 19. The running and starting windings are energized by the starting relay 20 which is connected to an electric supply, and, if desired, the compressor is caused to operate intermittently by placing in one of the electric lead lines a thermostatically operated snap switch 20a responsive to a temperature in the refrigerating apparatus, such as the temperature of the food compartment being cooled by the evaporator 12. The snap switch 20o thus operates in response to temperatures in the bulb 20b placed in the food compartment as is usual.

The evaporator 1-2 in this particular instance includes one or more refrigerated shelves 21 and 22 which receive the expanded refrigerant from the device 13 through the pipe 23. The refrig-' erant passes through the shelf 21, pipe 24, shelf 22, pipe 25 to the upwardly directed branches 26 and 27 which form the food storage cooling portion of the evaporator. The refrigerant then flows through the pipe 28 from the branch 2'? to the branch 26 and from thence through the pipe 29 to the trap 15 from which it flows through the pipe 30 to the compressor 10. In Fig. 1, the pipe 30 is shown with a portion upwardly directed on the drawing, but preferably this is to be taken as a plan view or diagrammatic representation of a construction in which the pipe 30 slopes downwardly to the compressor with substantially no upward slopes or with only slight or short upward slopes, and where such upward slopes are provided the pipe 30 is made sufiiciently small in diameter to sweep any liquid therein to the compressor with the gaseous refrigerant.

When the compressor 10 is stopped by the thermostat or for the defrosting operation, the expansion device 13, being continuously open, permits the flow of refrigerant from the high side to the evaporator, so that substantially all of the liquid refrigerant flows into the evaporator 12. When the compressor 10 is started, the liquid refrigerant standing in the evaporator 12 may froth into or spill over through the pipe 29 and, without my invention, would be delivered to the compressor 10 as a large body of liquid capable of damaging the compressor or of causing it to operate in a very noisy and undesirable manner. However, according to my invention, this liquid refrigerant is delayed in the trap 15 and is fed very slowly and at such a rate that the liquid has no perceptible effect on the compressor. To this end the refrigerant passes from the pipe 29 through the inlet 31 of the trap. From thence it passes through a filter 32 and then through the opening 33 of the bafi'ie 34. The outlet pipe 35 forms a liquid refrigerant dam, since it extends upwardly into the cas ing of the trap above the bottom thereof. It is provided with a substantially unrestricted gaseous refrigerant passage or intake 36 and with a restricted liquid refrigerant drain 37 below the gaseous refrigerant intake 36. Preferably this drain 37 is slightly above the bottom in order that any heavy foreign substances may settle out in the space 38 below the drain 37. When a large body of liquid refrigerant is discharged from the evaporator 12 into the trap 15, the liquid refrigerant' is delayed by the dam or pipe 35, but the gaseous refrigerant is permitted to flow substantially unrestricted through the passageway 36 to the compressor 10. A slight amount of liquid refrigerant is allowed to pass through the drain 37 and is picked up by the gaseous refrigerant and is carried to the compressor 10. The size of the drain 37 is such that the amount of liquid refrigerant passing through the pipe 30 is either insufiicient to harm the compressor 10 or to cause it to operate noisily, and, in fact, the amount of liquid refrigerant may be so slight, that it is evaporated entirely by atmospheric heat in the pipe 30 before it reaches the compressor 10. Thus by this construction, quiet operation of the compressor is insured during the starting periods of an intermittently operating refrigerating system and all danger of damage to the corlrlilpressor is removed.

the form shown in Fig. 2, the trap may be in the form of a casing 40 with the inlet 41 connected to the pipe 29and with the outlet 42 connected to the pipe 30. -The size and shape of the casing is proportioned with respect to the velocity of gaseous refrigerant'and volume of liquid refrigerant that the liquid is trapped or delayed in the casing 40. The continual bubbling of gaseous refrigerant through the liquid, and the evaporation of the liquid by atmospheric heat gradually introduce the liquid into the gas passing out through the outlet 42 at such a slow rate that the operation of the compressor is not disturbed. By this construction eventuallysubstantially all of the liquid entering through pipe 29 is gradually fed, in the form of liquid or gas, into the pipe 30 at a slow and satisfactory rate substantially as described with'respect to Fig. 1.

It is to be understood that while-the description has been made only with respect to the flow of gaseous and liquid refrigerant, if any lubricant flows through the cycle along with the. refrigerant, the lubricant will be delayed and forwarded to the compressor gradually in the same manner as the liquid refrigerant.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it.i s to'be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed isas followsr 1. A refrigerating apparatus comprising a compressor, a condenser and an evaporator in refrigerant flow relationship, and means interposed .betweensaid evaporator and compressor for arresting an abnormal flow of liquid refrigerant whilepermitting the flow of gaseous refrigerant and the flow of a relatively small quantity of arrested liquid refrigerant into the gaseous refrig-- erant flowing to the compressor.

2. A refrigerating apparatus comprising a compressor, a condenser and an evaporator in refrigerant flow relationship, and a trap inter- .posed between said evaporator and compressor having a liquid refrigerant dam, a substantially unrestricted gaseous refrigerant passage past said dam, and a restricted liquid refrigerant drain into said passage.

3. A refrigerating apparatus comprising a compressor, a condenser and an evaporator in refrigerant flow relationship, and a trap interposed between said evaporator and compressor, said trap comprising a casing having an inlet and an outlet pipe extending into said trap with its gaseous refrigerant intake above the bottom of said trap, said outlet pipe having a restricted liquid refrigerant drain below said gaseous refrigerant intake. 1

4. A refrigerating apparatus comprising a compressor, a condenser and an evaporator in refrigerant flow relationship, a continuously open refrigerant expansion device between said'condenser and evaporator, and means interposed between said evaporator and compressor for arresting the flow of liquid refrigeant while permitting substantially unrestricted flow of gaseous refrigerant and for gradually releasing the arrested liquid refrigerant toward the compressor.

5. A refrigerating apparatus comprising a compressor, a condenser and an evaporator in refrigerant flow relationship, a continuously open refrigerant expansion device between said condenser and evaporator, and means interposed between said evaporator and compressor for arresting an abnormal flow of liquid refrigerant while permitting the flow of gaseous refrigerant and the flow of a relatively small quantity of arrested liquid refrigerant with the gaseous refrigerant.

6. A refrigerating apparatus comprising a compressor, a condenser and an evaporator in refrigerant flow relationship, a continuously open refrigerant expansion device between said eondenser and evaporator, and a trap interposed between said evaporator and compressor having a liquid refrigerant dam, a substantially unrestricted gaseous refrigerant passage past said dam, and a restricted liquid refrigerant drain into said passage. I

7. A refrigerating apparatus comprising a compressor, a condenser and an evaporator in refrigerant flow relationship, a. continuously open refrigerant expansion device between said said evaporator and compressor, said trap comprising a casing having an inlet and an outlet pipe extending into said trap with its gaseous refrigerant intake above the bottom of said trap, said outlet pipe having a restricted liquid refrigerant drain below said gaseous refrigerant intake. 8. A refrigerating apparatus comprising a compressor, a condenser and an evaporator in refrigerant flow relationship, a continuously open refrigerant expansion device between said condenser and evaporator, means for intermittently operatingv the compressor, and means interposed between said evaporator and compressor for arresting an abnormal flow of liquid refrigerant while permitting the flow of gaseous refrigerant and the flow of a relatively small quantity ofarrested liquid refrigerant with the gaseous refrigerant. I

9. A refrigerating apparatus comprising a compressor, a condenser and an evaporator in refrigerant flow relationship, a continuously open refrigerant expansion device between said condenser and evaporator. means for intermittently 10. A refrigerating apparatus comprising a compressor, a condenser and an evaporator in refrigerant flow relationship, a continuously open refrigerant expansion device between said condenser and evaporator, means for intermittently operating the compressor and a trap between said evaporator and compressor, said trap comprising a casing having an inlet and an outlet pipe extending into said trap with its gaseous refrigerant intake above the bottom of said trap, said outlet pipe having a; restricted liquid refrigerant drain below said gaseous refrigerant intake.

CHARLES F. KE'I'I'ERING. 

